1. Field of the Invention
The present invention relates to a method of forming a photoresist pattern in a semiconductor device by multi exposure process using a plurality of photo masks, which makes a micro pattern required to an high integrated semiconductor device.
2. Information Disclosure Statement
In general, a micro pattern less than 0.25 .mu.m wide is required for an high integrated semiconductor device. The width of a pattern is determined by the wavelength of light. Therefore, a pattern less than 0.25 .mu.m wide can be formed by a stepper utilizing the Excimer Laser which generates a short wave length(.lambda.=248 nm).
However, when an ordinary stepper utilizing a G-line or I-line a relatively long wave length (.lambda.=436 nm or 365 nm) is used to form a micro pattern with a width of below minimum feature size (MFS), it is difficult to form a pattern of the profile and width required for an high integrated semiconductor device because of the lower contrast of the light.